Beam determining method performed during uplink random access, user equipment and base station

Abstract

A beam determining method performed in an uplink random access procedure, a user equipment, and a base station are disclosed. The user equipment has a plurality of RX beams, the base station has a plurality of TX beams. A beam determining method performed by a user equipment includes: determining an available RX beam among the plurality of RX beams of the user equipment and an available TX beam among the plurality of TX beams of the base station according to downlink synchronization signals transmitted by the base station; notifying the base station of information indicating the available TX beam of the base station implicitly.

What is claimed is: 
     
       1. A user equipment for performing beam selection and in communication with a base station comprising:
 a processor coupled to a transceiver, configured to select a transmitting beam among a plurality of transmitting beams of the base station corresponding to downlink synchronization signals transmitted by the base station, wherein a reception quality of the downlink synchronization signals is above a threshold; and 
 the processor coupled to the transceiver further configured to transmit a random access preamble to the base station on time-frequency resources corresponding to the selected transmitting beam of the base station, 
 wherein a corresponding relationship between various transmitting beams of the base station and various random access preambles is configured in the user equipment, 
 the processor coupled to the transceiver selects the random access preamble associated with the selected transmitting beam of the base station according to the configured corresponding relationship, 
 transmits the random access preamble associated with the selected transmitting beam to the base station, 
 receives a random access channel (RACH) configuration including information regarding a time length between the time-frequency resources and a response to the random access preamble, and 
 controls to receive the response based on the information. 
 
     
     
       2. The user equipment of  claim 1 , wherein the processor coupled to the transceiver selects the time-frequency resources of the random access preamble corresponding to the selected transmitting beam of the base station according to a corresponding relationship between time-frequency resources of the random access preambles and the various transmitting beams of the base station. 
     
     
       3. A beam selection method performed by a user equipment in communication with a base station, comprising:
 selecting a transmitting beam among a plurality of transmitting beams of the base station corresponding to downlink synchronization signals transmitted by the base station, wherein a reception quality of the downlink synchronization signals is above a threshold; 
 transmitting a random access preamble to the base station on time-frequency resources corresponding to the selected transmitting beam of the base station, 
 wherein a corresponding relationship between various transmitting beams of the base station and various random access preambles is configured in the user equipment, and the method further comprises: 
 selecting the random access preamble associated with the selected transmitting beam of the base station according to the configured corresponding relationship; 
 transmitting the random access preamble associated with the selected transmitting beam to the base station, 
 receiving a random access channel (RACH) configuration including information regarding a time length between the time-frequency resources and a response to the random access preamble, and 
 controlling to receive the response based on the information. 
 
     
     
       4. The method of  claim 3 , wherein selecting the time-frequency resources of the random access preamble corresponding to the selected transmitting beam of the base station according to a corresponding relationship between time-frequency resources of the random access preambles and the various transmitting beams of the base station. 
     
     
       5. A base station comprising:
 a processor coupled to a transceiver, configured to transmit, to a user equipment, a plurality of transmitting beams corresponding to downlink synchronization signals to select a transmitting beam among the plurality of transmitting beams by the user equipment, wherein a reception quality of the downlink synchronization signals, selected by the user equipment, is above a threshold; and 
 the processor coupled to the transceiver further configured to receive a random access preamble on time-frequency resources corresponding to the selected transmitting beam, 
 wherein the processor coupled to the transceiver transmits a corresponding relationship between various transmitting beams and various random access preambles to the user equipment, 
 the processor coupled to the transceiver receives the random access preamble associated with the selected transmitting beam selected by the user equipment according to the corresponding relationship, 
 transmits a random access channel (RACH) configuration including information regarding a time length between the time-frequency resources and a response to the random access preamble, and 
 controls to transmit the response based on the information. 
 
     
     
       6. A system comprising a base station and a user equipment, wherein:
 the base station comprises:
 a first processor coupled to a transceiver, configured to transmit, to the user equipment, a plurality of transmitting beams corresponding to downlink synchronization signals to select a transmitting beam among the plurality of transmitting beams by the user equipment, wherein a reception quality of the downlink synchronization signals, selected by the user equipment, is above a threshold; and 
 the first processor coupled to the transceiver further configured to receive a random access preamble on time-frequency resources corresponding to the selected transmitting beam, 
 wherein the first processor coupled to the transceiver transmits a corresponding relationship between various transmitting beams and various random access preambles to the user equipment, 
 the first processor coupled to the transceiver receives the random access preamble associated with the selected transmitting beam selected by the user equipment according to the corresponding relationship, 
 transmits a random access channel (RACH) configuration including information regarding a time length between the time-frequency resources and a response to the random access preamble, and 
 controls to transmit the response based on the information, and 
 
 the user equipment comprises:
 a second processor coupled to a second transceiver, configured to select the transmitting beam among the plurality of transmitting beams corresponding to the downlink synchronization signals, wherein the reception quality of the downlink synchronization signals is above the threshold; and 
 the second processor coupled to the second transceiver further configured to transmit the random access preamble to the base station on the time-frequency resources corresponding to the selected transmitting beam of the base station, 
 wherein the second processor coupled to the second transceiver of the user equipment selects the random access preamble according to the corresponding relationship transmitted by the base station, 
 transmits the random access preamble to the base station, 
 receives the RACH configuration including the information, and 
 controls to receive the response based on the information.